Antimony Chalcogenide van der Waals Nanostructures for Energy Conversion and Storage
Among van der Waals nanomaterials, topological insulators such as antimony chalcogenides (Sb2X3, X = S, Se, Te) have interesting thermoelectric and optical properties. Expressly, Sb2S3 is regarded as a favorable anode material for batteries owing to its predicted specific capacity. Both Sb2S3 and Sb2Se3 have an isomorphous tubular one-dimensional (1D) crystal structure, whereas Sb2Te3 has a two-dimensional (2D) layered structure. The synthesized bulk crystals of Sb2X3 were submitted to liquid-phase shear force exfoliation. The 1D and 2D Sb2X3 undergo downsizing processes, also complemented by delamination, to submicron sheets and with an average thickness down to 37 nm. The inherent electrochemical and heterogeneous electron transfer properties of the materials were first studied. Exfoliated Sb2S3 had the best performance for the hydrogen evolution reaction in a wide pH range, with improvements in the overpotential of up to 500 mV, with respect to the starting material. Specifically, in acidic media, exfoliated Sb2S3 also has a good stability for multiple cycles and continuous operation. Likewise, exfoliated Sb2S3 had the highest gravimetric capacitive behavior in alkaline solution.